This invention relates to filter units such as those commonly used in cylindrical filter assemblies. More specifically, this invention relates to integral filter core extenders and sealing devices which are used to provide connecting and sealing means between adjacent cartridge filters as well as to provide structural integrity to a plurality of adjacent cartridge filters.
Filtration is one of the most common operations conducted in conjunction with a multitude of industrial processes. Typically, suspended solids are removed from liquid streams in order to recover the solids as a product or to provide a filtered liquid product stream. Under certain conditions the filtration operation rapidly becomes ineffective due to the filter having reached its filtration capacity, thus requiring cleaning of the filter medium. In order to avoid time-consuming filter cleaning procedures, cartridge filters were introduced in order to provide for ease of filter replacement.
Typically, cartridge filters are stacked within a filter housing containing a support rod, often metal, that positions the filter cartidges. The support rod is inserted through the filter cartidges by way of longitudinal bores or cavities therein. One disadvantage with respect to the use of these support rods to position the cartridges is that the rods are frequently crushed when the filters fail due to overloading or excessive pressure drop. Additionally, even when the support rod does not fail, collapse of the filter onto said rod makes it extremely difficult to separate the rod from the filter medium for re-use. Replacement of the support rods is an expensive and time-consuming process.
In addition, a problem frequently arises concerning the prevention of leakage of liquid filtrate between adjacent annular surfaces of cartridge filters within a filter housing. It is difficult to provide a stacked coaxial assembly of cartridge filters which are pressed together in such a manner so as to prevent leakage of liquid through the adjacent annular surfaces.
It is thus an object of this invention to provide an improved means for positioning and supporting cartridge filters within a filter housing.
It is also an object of this invention to provide an improved means to connect adjacent filter cartridges within a filter housing.
A still further object of this invention is to provide an improved means to form a more effective seal between adjacent cartridge filters in a filter housing.